Resource devices manage computing resources. There are a myriad of examples of such computing resources, extending from data storage on disk drives in storage arrays to connection processing within high volume content servers in server farms. Typically, resource devices comprise a plurality of resource nodes, thereby forming a distributed resource that appears as a single, logical resource device from the perspective of a resource consumer.
The resource nodes responsible for managing the physical resources, whether the resource nodes manage a data storage resource-or is an individual web server responsible for connection and content resources, must function efficiently, especially in complex environments comprising many resource consumers and resource devices. The efficiency depends on desirable characteristics including scalability, high performance, load balancing, low response times (responsiveness), or others characteristics that could require optimization. Resource nodes are typically either managed by external management systems, or have a management layer imposed on them, which unfortunately introduces extra overhead beyond the core responsibility of resource management. A resource device comprising a plurality of resource nodes exacerbates the external management problem. For example, as resource nodes become loaded, they typically inform resource consumers of their state, shift resource requests to other resource nodes, or perform other out-of-band management communications to maximize performance resulting in excessive out-of-band communication. Such systems suffer from scalability issues because as new resource nodes are added to the environment, the management “chatter” increases subtend a larger fraction of communication and processing bandwidth, which negatively impacts performance. Due to such coarse grained scalability, the cost to incrementally enhance the capability of the system increases, and the cost to replicate the entire system becomes prohibitive.
To reduce costs and achieve other desirable results, it is advantageous to design a system in which each individual resource node functions independently of other resource nodes or external management systems. In other words, a resource node should not require information regarding other resource nodes to perform its primary responsibility of managing a resource. To service resource consumers who desire access to a resource, autonomous resource nodes should determine when to process commands from a resource consumer based upon, or at least determined as a factor of, (a) information relating to the resource node and (b) any information supplied by the resource consumer within the message comprising the command.
Beyond supplying command information, resource consumers supply information regarding their desired urgency or importance for having a command processed. When resource consumers understand the behavior of the autonomous resource nodes, benefits of scalability, performance, or responsiveness are achieved naturally, without imposing additional functionality, because resource consumers are able to adjust their resource command messages based upon the interactions with all the resource nodes to gain higher performance.
Current related art attempts to provide efficient access to computing resources by focusing on activities external to resource consumer-resource node interactions rather than on the natural behavior resulting from their interactions. The related art imposes additional functionality to optimize desirable characteristics. For example, related art might require resource consumers to communicate with other resource consumers, resource nodes to communicate with other resource nodes, or communicate with a communication path to manage communications between resource consumers and resource nodes.
Sun Microsystems' U.S. Pat. No. 5,506,969 titled “Method and apparatus for bus bandwidth management” teaches how to efficiently schedule bus accesses from multiple applications to peripheral modules on a high-speed bus. Although the patent describes how the bus between the applications and modules is managed, it requires a bus management system rather than allowing the individual module's and application's behavior to have the desired performance result. The applications do not employ resource command messages comprising of urgency or importance information that allows the modules to determine when to process requests.
Hewlett Packard Development Company's U.S. Pat. No.6,886,035titled “Dynamic load balancing of a network of a client and server computer” teaches how client computers optimize throughput between themselves and a resource through the use of redirection. Redirection requires a host the network to be knowledgeable of other hosts on the network beyond itself. The scalability of the system is reduced because each additional element added to the system must be managed and incorporated into the system to ensure it has sufficient knowledge for redirection. The load-balancing is not achieved naturally as it would be through the use of urgency or importance information within commands messages.
EMC Corporation's U.S. Pat. No. 6,904,470 titled “Device selection by a disk adapter scheduler” teaches how to efficiently schedule resource I/O requests of based upon urgency and priority of requests. The patent describes how a main scheduler determines what type of scheduler should be used to manage various I/O tasks directed toward logical volumes managed by a disk adapter. Although logical volumes are associated with physical data storage resources, they are a coherent virtual device. Therefore, each disk adapter is responsible for a device rather than a resource and imposes additional management capabilities to ensure load-balancing, performance, and other qualities across the logical volumes. The '470 patent does not address the autonomous behavior of a resource node whose behavior naturally results from the use of urgency or importance information used along with the resource node information to determine when tasks are issued.
None of the related art addresses the need for autonomous resource nodes whose behavior naturally results in desired characteristics including scalability, high performance, load balancing, or responsiveness. To fully realize the benefits of autonomous resource nodes, a solution would preferably include the following characteristics:                Resource nodes determine when to handle commands from resource consumers based upon information relating to the command and relating to the resource node's own information        Messages sent from resource consumers to resource nodes indicate the resource consumer's sense of urgency or importance related to processing the message or the command within the message        
Resource nodes that are able to determine when to handle commands sent to them result in several advantages. First, each individual resource node focuses on its main responsibilities rather than on other non-resource centric tasks; therefore, the resource node functions with a higher efficiency than a similar resource node that has additional management tasks to perform. Second, multiple resource consumers are able to interact with multiple resource nodes of a resource device without an extraneous arbitrator. This results in improved response time because each resource node is able to determine independently which resource consumer deserves (if applicable) attention. Third, when multiple resource nodes provide access to redundant resources, and the resource nodes are addressed simultaneously, the collection of resource node automatically load balance because each resource devices functions to its fullest capabilities. If one redundant resource node is fully loaded, another redundant resource node is able to service requests without external intervention. Additionally, any of the redundant resource nodes are capable of providing a valid response to a resource consumer; therefore, the responsiveness of the system is higher than a resource device without redundant resource nodes. Fourth, the scalability of such an environment is high because each resource node is independent and does not require additional information from resource consumers or other resource nodes and can integrate into the environment easily. Although only a few advantages are presented, other contemplated advantages are naturally inherent in the presented subject matter.
Thus, there remains a considerable need for methods and apparatus that provide for resource command messages and resource devices comprising one or more resource nodes that autonomously determine when to process resource command messages based upon the contents of the command message and on information associated with the resource node.